2 options: business hw or cheap pc with linux (Score 1)

A little overkill perhaps, but something like this (around $500) is a good option.... http://www.juniper.net/us/en/products-services/security/ssg-series/ssg5/ Alternatively, pretty much any PC with two network interfaces running something like Smoothwall or IPCop should do the trick: http://en.wikipedia.org/wiki/List_of_Linux_router_or_firewall_distributions